Studies in zymasis

TOWARDS the end of the nineteenth century it was realised that the cells of many higher plants could form ethyl alcohol in the absence of oxygen [see literature quoted by Kostytschew, 1927], and several workers made simul- taneous measurements of the production of ethyl alcohol and CO2 in anaerobiosis.Recent comparisons of anaerobic and aerobic metabolism have led to an alteration of biological outlook on cell respiration in animals, yeast and bacteria.It was shown by Blackman [1928] that the cells of higher plants fall into line with those of other organisms.Blackman based his conclusions on measurements of the CO2 output of stored Bramley's Seedling apples in air and in nitrogen.At that time he made the primary assumption in his paper that the ratio C02/ ethyl alcohol in the anaerobic respiration of this variety is unity.For example, he wrote, "in nitrogen, Group D (by which he implies intermediate compounds between hexoses and ethyl alcohol) proceed quantitatively to the two final products CO2 and alcohol in the usual ratio," and, "it will be held that for one atom of carbon thus detected (as C02) there are two atoms of carbon ex- creted into the tissues as alcohol."Actually, as will be pointed out later, the precise value of the ratio C02/ethyl alcohol, although affecting his arithmetical